Pentaxians might complain about why Metabones didn't make their "Speed Booster" in K-mount? I think it is just a market(ing) decision after all.
Still, if you want to get something similar to use, i.e., to put your old Pentax FF lenses onto the current APS-C cropped body, here is an alternative solution:-
http://www.sonyalpharumors.com/first-pictures-of-the-cheap-chinese-speed-booster-alternative-to-ship-from-may-already/
But I really doubt about the resulting IQ anyway. Still, I don't think it is wise enough to do so, especially consider about the huge cost of the original Speed Booster.
Speaking of those Chinese made adaptors, actually one can find almost anything nowadays, for whatever one would want (to convert)! For example, here is yet an EOS lens to NEX body adaptor, which even supports full AF and AE (auto aperture) functions, and the EOS lenses could now fully work on the NEX bodies just like what they can on the EOS M body, with the need of an adaptor also!
http://detail.tmall.com/item.htm?id=18431707112&ali_refid=a3_420434_1006:1103341686:6::1956d6a4d06e6ea3dc9c71d2c005f1fe&ali_trackid=1_1956d6a4d06e6ea3dc9c71d2c005f1fe
(in Chinese)
It is warned that the AF will be slower, though. But this is also the result with the original EOS lenses when they are put onto the EOS M body via an adaptor, which is yet original! >:-(
Related:-
K-5D Mark III: DA 18-55 II Converted to a 24-80 FULL FRAME Lens!